1. Field of the Invention
This invention relates to new, improved beta-diketones and their use in the extraction of copper from aqueous ammoniacal solutions containing copper values, resulting from commercial processes, including, but not limited to, leaching of copper containing ores, such as sulfidic ores, or concentrates resulting from flotation of such sulfidic ores.
2. Statement of Related Art
Practice in the recovery of copper from its sulfidic ores involves subjecting the ores to a froth flotation operation to produce a concentrate of the valuable metal sulfides and to reject the flotation tailings of valueless sulfides, silicates, aluminates and the like. One of such concentrates provided is a chalcocite concentrate containing chalcocite and covellite.
In U.S. Pat. No. 4,022,866 to Kuhn and Arbiter, and in their subsequent paper, "Physical and Chemical Separations via the Arbiter process" 11th International Mining Congress, April, 1975, Cagliari, Italy; proc.-Int. Miner. Process. Congress., paper 30; pp.831-847; there is described the leaching of copper sulfide concentrates with ammonia/ammonium sulfate and oxygen whereby the sulfate, and the dissolved copper may then be recovered by solvent extraction. The solvent extraction reagents are described in the patent only generally as those which preferentially load copper from alkaline solutions. In the paper, which describes the Arbiter process, the focus is on complete or nearly complete leaching of the concentrate. Another Kuhn and Arbiter paper, "Anaconda's Arbiter Process for Copper", Hydrometallurgy, CIM Bulletin, February, 1974, contains similar description.
U.S. Pat. No. 4,563,256 describes a solvent extraction process for the recovery of zinc values from ammoniacal solutions, which may also contain copper values, using or employing various oxime extractants.
U.S. Pat. No. 2,727,818 describes a method of leaching copper sulfide materials with ammoniacal leach solutions. No solvent extraction is discussed.
U.S. Pat. Nos. 4,065,502 and 4,175,012 describes beta-diketones which may be employed as metal extractants in a liquid--liquid ion exchange process for recovery of metals, such as nickel or copper, from aqueous solutions containing the metal values, including aqueous ammoniacal solutions.
U.S. Pat. No. 4,350,661 describes the extraction of copper from ammoniacal aqueous solutions by a process of extraction first with a beta-diketone followed by a second extraction with an oxime. Alternatively, there is described the use of a mixture of diketone and oxime wherein the extractant reagent comprises about 5-30 percent by volume of the strong reagent (oxime) and 10-60 percent by volume of the weak reagent (beta diketone).
In commonly assigned, application, U.S. Ser. No. 07/745,028, Australian Patent No. 668358, issued Aug. 20, 1996, corresponding thereto, there is described a partial leaching of a chalcocite concentrate, to provide an aqueous ammoniacal leach solution containing copper values, and the use of high copper transfer, low ammonia loading extraction reagents such as a beta-diketone. An oxime extractant is also disclosed alone or with the diketone.